The present invention relates to a method for operating a power window apparatus for automatically opening and closing a window of an automobile, and more particularly to a method for operating a power window apparatus with a safety device which carries out a safety control operation when the hand, neck, etc., of a driver or passenger is caught between the window glass and the sash.
Recent automobiles are often provided with a power window apparatus for automatically opening and closing the windows. In such a power window apparatus, however, a dangerous situation occurs if the hand or neck of a passenger is accidentally caught between the window and the sash. To cope with this situation, a safety device has been proposed. The safety device operates such that when it detects a state where an object, for example, the hand of a passenger or driver, is caught between the window glass and the sash, the movement of the window glass is stopped or the window glass is forcibly moved in the opening direction.
In this apparatus, a detector for detecting the rotational speed of the motor used for driving the window glass is provided. When an object is caught in the window glass, the motor speed is reduced. The motor speed detector detects this reduction of the motor speed. When the speed reduction is detected, the safety device forcibly opens the window, that is, carries out the safety control operation, so as to release the caught object.
In a situation where the window glass approaches the fully closed position and comes into contact with the sash, for example, and the motor speed is reduced, the safety device sometimes mistakenly recognizes this normal occurrence of speed reduction as an object being caught in the window, and mistakenly carries out the safety control operation. In this case, the window is left incompletely closed.
To cope with this problem, a safety control mode disabling region is provided. In this region, the safety control mode is disabled in a region just before the window is completely closed. With the provision of the safety control mode disabling region, complete closure of the window glass is possible.
The motor of the power window apparatus is provided with a damper for damping impacts applied to the window. Accordingly, after the window is fully closed, the rotation of the motor continues for a time period corresponding to the quantity of deformation of the damper. Therefore, if the fully closed state of the window glass is detected on the basis of the rotation of the motor, the detected position of the fully closed state of the window glass exceeds the actual position, i.e., it is deviated from the latter.
If the deviation is a fixed quantity, it is easy to obviate the adverse effects caused by such deviation. In actuality, however, the deviation varies depending on ambient conditions, for example, temperature. When the deviation varies, the safety control mode disabling region varies since it is established on the basis of the fully closed position of the window. If an object-caught state is erroneously detected as the result of such deviation, the problem of the window being left in an incompletely closed state again occurs.